The Langsdorff’s expedition to Brazil and its mammal collection kept in the Zoological Institute of St. Petersburg, RussiaAbramov A.V., Baranova G.I.P. 41-50All the available collecting data on the mammal collection made during the 1822-1829 Brazil expedition under the leadership by G.I. Langsdorff are provided. The collection is kept in the Zoological Institute of the Russian Academy of Sciences, St. Petersburg and at present contains 184 specimens of 74 species and 26 families of the orders Didelphimorphia, Cingulata, Pilosa, Primates, Lagomorpha, Chiroptera, Carnivora, Perissodactyla, Artiodactyla, and Rodentia.